Sundial



March 2, 1937. F, W MQEHLE 2,072,565

SUNDIAL Filed Aug. 17, 1935 firm/mfr #1f/70eme,

Patented Mar. 2, 1937 UNITED STATES SUNDIAL Frederick W. Moehle,Attleboro, Mass., assignor to The Robbins Co., Attleboro, Mass., acorporation of Massachusetts Application August 17, 1935, Serial No.36,627

1 Claim.

The present invention relates to a sun dial, and more particularly to areadily portable or pocket sun dial which may be conveniently carried onthe person.

An object of the present invention is to provide a pocket sun dialwhereby apparent solar time may be observed.

Another object of the present invention is to provide a pocket sun dialwith a calibrated time indicating card so mounted as to be adjustable tocompensate for ascertainment of time in different meridian positions,and also for different seasons of a year.

The sun dial of the present invention may be conveniently carried on theperson, and once having been adjusted for any particular meridianposition, and season, may be utilized at any hour of daylight toindicate solar time.

The above, other and further objects of the present invention will beapparent from the following description and accompanying drawing.

An embodiment of the present invention is illustrated in theaccompanying drawing, and the views thereof are as follows:

Figure l is a perspective view of the sun dial oi the present invention,which is adapted to be suspended and swing, and shown in partly swungposition to illustrate the relationship between the time card and theaperture in the dial through which the suns rays enter against the card.

Figure 2 is a development of the card utilized.

Figure 3 is a sectional view taken substantially in the plane of theline III- III of Figure l, illustrating certain details of construction.

The drawing will now be explained.

The sun dial, as illustrated herein, comprises a' ring I, of aluminum,brass or other suitable material, having an aperture 2 in it whereby itmay be suspended as by a cord 3, for use. Angularly 40 spaced from theaperture 2, a distance of approximately 40 to 45, is an aperture 4,through which the suns rays, indicated by the line 5, may enter andstrike the time card 6, to approximate the' apparent solar timeobserved.

'Ihe calibrated time strip or card 6 is provided with indiciarepresenting time for fifteen hours arranged on the card with the hours5 to l2 inelusive for A. M. time as on one side of a median line 'l andthe indicia for the hours from 1 to 7 P. M. time arranged on theopposite side of the median line. Crossing the median line 'I are aplurality of perpendicular lines, represented generally at 8, toindicate the hourly divisions of time, and other intermediate lines 9 toindicate divisions of hourly time, such as intervals of ten minutes.Preferably, for ease in observation, the lengths of the lines 8 and 9are different. In addition the hour lines 8 have characteristics ornumerals I I! representing the hours of the day, to facilitateobservation. 5

The card is marked to indicate A. M. and P. M. time, as may be observedby reference to Figure 2, and also the card is marked as Standard time.

In order to mount the card 6 inthe ring I,vso as to be adjustable alongthe inner periphery of the ring, sliding clips II are provided. Each ofthe clips II includes a part I2 to bear against the outer periphery ofthe ring I, and inturned lugs I3 to engage, in slightly spaced relationto the inner periphery of the ring, the extremities of 15 the card 6when installed, as shown in Figure 1.

The sun dial is used by suspending it from the cord 3, held in the handof the observer, and the plane of the dial is turned so that the sunsrays fall directly on the aperture 4, entering such ap- 2O erture andstriking the card 6 at some point. Where the suns rays 5 strike the cardE, a small dot oi light appears, depending of course on the size of theaperture 4. This dot then indicates the apparent solar time on the dial.25

The observer, if the card 6 is not adjusted in the dial, toapproximately represent the apparent solar time of the meridian positionof the observer, slides the clips II in such a manner as to loosen thecard 6, and then the card is moved 30 endwise to so position it withreference to the aperture 4, so that any ray from the sun entering theaperture will indicate approximately the apparent solar time at themoment of observation, which adjustment may be checked by a watch or 35clock.

It will thus be observed that by means of the sun dial of the presentinvention, the dial may be made in quantity lots and utilized in anypart of the world for indicating apparent solar time. The use of theadjustably mounted time card 6, makes this possible, as the card may beadjusted to suit any point of observation on the earths surface.

When using the sun dial for determination of 45 A. M, time, the aperture4 is towards the east, while for determining P. M. time, it is towardthe west. In other words, the ring is so positioned that the aperture 4is towards the sun.

The adjustability of the card 6 enables use o1' 50 but a single card fordifferent meridian positions and also for different seasons of the year.

I am aware that many changes may be made and numerous details ofconstruction may be varied through a wide range Without departing 55from the principles of this invention, and I, therefore, do not purposelimiting the patent granted hereon otherwise than necessitated by theprior art.

The invention is claimed as follows:

A pocket sun dial comprising a flat annular band having means whereby itis adapted to be suspended in a vertical plane with the plane thereofcoincidental with the direction of the sun from 10 the abserver, saidband having means defining a pinhole aperture therethrough at a xedpoint for the projection of sunlight therethrough to an opposed innerface of the band, a graduated strip movably seated on said opposed innerface, means to removably secure said strip to said band, said meanscomprising clips slidable on the outer face of said band and havinginturned end portions to overlie marginal portions of said strip forguided movement of said strip.

FREDERICK W. MOEHLE.

